A woman pushes a child on a tricycle in the centre of Yuzhno-Kurilsk, the main settlement on the island of Kunashiri. Moscow’s claim to the island and its three neighbours, which were annexed during the second world war, is disputed by the Japanese government.
Photograph: Thomas Peter/Reuters

Vladimir Putin’s highly anticipated visit to Japan has been postponed indefinitely, amid anger in Tokyo at Moscow’s stance on a long-running territorial dispute and concern about Russia’s involvement in the Syrian conflict.

The Russian president was to have visited Tokyo by the end of the year to hold talks with Japan’s prime minister, Shinzo Abe, on the Northern Territories, a group of four islands seized from Japan by the Soviet Union towards the end of the second world war.

The dispute over the islands has prevented the two countries from signing a postwar peace treaty and soured ties between successive administrations.

Japan has accused Russia of frustrating negotiations over the islands, known as the Kurils in Russia, by approving recent visits by senior politicians, including the prime minister, Dmitry Medvedev, in August.

“We are closely watching the situation in Syria and the bombing by the Russian air force,” a foreign ministry official told the Guardian. “If it turns out that they are targeting elements that are not [Islamic State] then that may lead to a deterioration in the situation, and we have concerns about that.”

The official, who asked not to be named, said Japan would continue to push for the negotiated return of the four Northern Territories – Etorofu, Kunashiri, Shikotan and the Habomai islets – before concluding a peace treaty with Moscow.

But he added: “Visits to the islands by the Russian prime minister and ministers are of course something we cannot accept. But we need to resolve the islands issue first because that is the source of all of the problems we are having now.”

Kyodo News quoted unnamed Japanese government sources as saying that Putin’s visit would be “difficult to realise” by the end of the year, adding that Russian airstrikes in Syria had also made it “tough” to arrange. Putin will not be among the leaders attending the G7 summit in Japan next year after Russia was banished from the group following its annexation of Crimea last year.

But Japan’s chief cabinet secretary, Yoshihide Suga, said Tokyo would continue to explore the possibility of a visit this year, as agreed between Putin and Abe at last November’s Apec summit in Beijing.

Japan and Russia have failed to make progress on the sovereignty dispute despite numerous rounds of talks. Japan insists that all four islands should be returned, while Russia cites a 1956 agreement under which it would return the two smaller, less developed islands, but only after the countries sign a peace treaty.

Shinzo Abe and Vladimir Putin may have shaken hands at the UN last month, but frostiness between the two has torpedoed bilateral talks due for later this year. Photograph: Mikhail Klimentyev/AP

Located in the northwest Pacific near the northernmost Japanese island of Hokkaido, the Northern Territories are surrounded by rich fishing grounds, mineral deposits and possibly offshore oil and gas reserves. Many of the 17,000 Japanese living there at the end of the war were forced to leave. The islands are now inhabited by about 14,000 Russians.

Japan accused Russia of damaging the prospects for a breakthrough after Moscow said in June that it would accelerate building work on civilian and military infrastructure on the islands. Medvedev said the government would spend 70 billion roubles (£730m) on developing the territories over the next decade.

Japan is embroiled in territorial rows on three fronts: with Russia over the Northern Territories, with China over the Senkaku islands, and with South Korea over the Takeshima islands.